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Python Programming - Encapsulation

Exercise : Encapsulation - General Questions
  • Encapsulation - General Questions
86.
In Python, what is the benefit of using a private variable with a double underscore prefix, such as __quantity? 
class Inventory:
    __quantity = 0

    def update_quantity(self, quantity):
        Inventory.__quantity += quantity
It improves code maintainability by hiding implementation details
It allows unrestricted access to __quantity
It exposes all internal details of __quantity
It creates a global variable
Answer: Option
Explanation:
Encapsulation with a double underscore prefix improves code maintainability by hiding the implementation details of the class attribute __quantity.
87.
What is the primary purpose of the following Python class? 
class Book:
    def __init__(self, title, __author):
        self.title = title
        self.__author = __author

    def get_author(self):
        return self.__author
To create a new instance of the class
To provide controlled access to the 'author' variable
To define a public variable 'author'
To allow unrestricted access to the 'author' variable
Answer: Option
Explanation:
The get_author() method provides controlled and read-only access to the private variable '__author', demonstrating encapsulation.
88.
How can encapsulation be enforced in Python to make a variable 'serial_number' accessible only within its own class? 
class ElectronicDevice:
    def __init__(self, serial_number, __brand):
        self.serial_number = serial_number
        self.__brand = __brand
Use a getter method for 'serial_number'
Add a single underscore prefix before 'serial_number'
Make 'serial_number' a global variable
Add a double underscore prefix before 'serial_number'
Answer: Option
Explanation:
Adding a double underscore prefix before 'serial_number' makes it a private variable, enforcing encapsulation within the class.
89.
Consider the following Python code: 
class Circle:
    def __init__(self, __radius):
        self.__radius = __radius

    def calculate_area(self):
        return 3.14 * (self.__radius ** 2)
What is the purpose of the calculate_area() method?
To retrieve the area of the circle
To set a new area for the circle
To calculate the area of the circle
To expose all internal details of the class
Answer: Option
Explanation:
The calculate_area() method calculates and returns the area of the circle, demonstrating encapsulation.
90.
In Python, what is the benefit of using a private variable with a double underscore prefix, such as __weight? 
class Product:
    __weight = 0

    def update_weight(self, weight):
        Product.__weight += weight
It improves code maintainability by hiding implementation details
It allows unrestricted access to __weight
It exposes all internal details of __weight
It creates a global variable
Answer: Option
Explanation:
Encapsulation with a double underscore prefix improves code maintainability by hiding the implementation details of the class attribute __weight.
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